1. Field of the Invention
This invention relates to vascular balloon catheters which may be used for percutaneous transluminal angioplasty procedures, or alternatively may be used to position and expand a reinforcing stent within a blood vessel. In particular, this invention is especially adapted to treatment of small diameter blood vessels within the brain and may, for example, be used to temporarily occlude a blood vessel to evaluate the results of the occlusion prior to placing a permanent occlusion device within the vessel.
2. Description of the Prior Art
Medical catheters exist for a wide variety of purposes, including diagnostic procedures and interventional therapy, such as drug delivery, drainage, and perfusion. Catheters for each of these purposes may be introduced to numerous target sites within a patient""s body by guiding the catheter through the vascular system. A wide variety of specific catheter designs have been proposed for such different uses.
Of particular interest to the present invention, small diameter tubular access catheters are presently being used for diagnostic and interventional therapy techniques for vessels within the brain, such as the imaging and treatment of aneurysms, tumors, arteriovenous malformations, and fistulas. Such techniques place a number of requirements on the catheters that are to be employed. The primary requirement is size. The blood vessels in the brain are frequently as small as several millimeters, or less, requiring that catheters have an outside diameter as small as one French (0.33 millimeters). In addition to small size, the brain vasculature is highly tortuous, requiring that catheters used in vessels of the brain be very flexible, particularly at their distal ends, to pass through the regions of tortuosity. Additionally, the blood vessels of the brain are relatively fragile, so it is desirable that the catheters have a soft, non-traumatic exterior to prevent injury.
One problem frequently encountered with dual lumen catheters is the tendency of the outer body and inner body to longitudinally shift as the catheter is advanced through a blood vessel. U.S. Pat. Nos. 5,514,073 and 5,711,754, both to Miyata, et al., disclose an intra-aortic balloon catheter with an inner tube continuously affixed to the inner wall of a catheter tube. Such a construction results in a catheter body which is very stiff making such a catheter difficult to navigate through the tortuous vasculature of the brain.
In accordance with the present invention, there is a balloon catheter which includes a catheter body having an outer tubular member with a tubular wall and a lumen extending therethrough. The outer tubular member further has a proximal end and a distal end, and an inner surface and an outer surface. The catheter body further includes an inner tubular member having a tubular wall and a lumen extending therethrough. The inner tubular member further has proximal and distal ends, and inner and outer surfaces. The inner tubular member is disposed coaxially within the lumen of the outer tubular member. The outer surface of the inner tubular member is bonded to the inner surface of the outer tubular member at a plurality of discrete bonding locations. The discrete bonding locations are preferably substantially elliptical with a major axis of about 0.02 inches in length and are separated by about 0.1 inches. The discrete bonding locations preferably begin at a point approximately 1 inch proximal to the distal end of the outer tubular member and progress proximally along the length of the catheter body. The balloon catheter also includes an inflatable balloon having a main body portion, a proximal portion, and a distal portion. The proximal and distal portions extend from the main body portion. The proximal portion of the balloon is bonded to the distal end of the outer tubular member and the distal portion of the balloon being bonded to the distal end of the inner tubular member. In addition, the balloon catheter includes a coupling member having a lumen extending therethrough. The coupling member is mounted on the proximal end of the outer tubular member and the lumen of the coupling member communicates with the lumen between the outer tubular member and the inner tubular member so that fluid may be injected into the lumen of the coupling member to inflate the balloon.
In accordance with another aspect of the present invention, there is provided a balloon catheter which includes a catheter body. The catheter body includes an outer tubular member having a tubular wall and having a lumen extending throughout the length of the outer tubular member. The outer tubular member further has a proximal end and a distal end, and an inner surface and an outer surface. The catheter body further includes an inner tubular member having a tubular wall and having a lumen extending throughout the length of the inner tubular member. The inner tubular member also has a proximal end and a distal end, and an inner surface and an outer surface. The inner tubular member is disposed coaxially within the lumen of the outer tubular member. The outer surface of the inner tubular member is bonded to the inner surface of the outer tubular member at a plurality of discrete locations thereby forming a plurality of tack junctions. The balloon catheter further includes an inflatable balloon having a main body portion, a proximal portion, and a distal portion. The proximal and distal portions extend from the main body portion. The proximal portion of the balloon is bonded to the distal end of the outer tubular member and the distal portion of the balloon being bonded to the distal end of the inner tubular member. Finally, the balloon catheter includes a coupling member having a lumen extending therethrough. The coupling member is mounted on the proximal end of the outer tubular member and the lumen of the coupling member communicates with the lumen between the outer tubular member and the inner tubular member so that fluid may be injected into the lumen of the coupling member to inflate the balloon.
In accordance with another aspect of the present invention, the distance between each tack junction is preferably approximately 0.1 inches.
In accordance with another aspect of the present invention, at least one tack junction is preferably between about 0.01 inches and 0.1 inches in length.
In accordance with another aspect of the present invention, at least one tack junction is preferably substantially elliptical with a major axis between about 0.01 inches and 0.1 inches in length.
In accordance with another aspect of the present invention, the tack junctions are preferably of various lengths.
In accordance with another aspect of the present invention, the tack junctions are preferably of a substantially uniform length.
In accordance with another aspect of the present invention, the plurality of tack junctions are preferably aligned along the length of the catheter with the most distal tack junction being near the distal end of the outer tubular member.
In accordance with another aspect of the present invention, the most distal tack junction is preferably approximately 1 inch from the distal end of the outer tubular member.
In accordance with another aspect of the present invention, the diameter of each tack junction is preferably about 0.02 inches in length.